Re: Bar lines

[Noeck]

>> a)
>> In a text I'd write
>> p.e
>>   "
>>    This is the "Barform":
>>    |: Stollen :|
>>      Abgesang
>>   "
As these symbols (|: :|) need a \bar command around and as \repeat is
the command to be used for repeats, there is no need for that, imho.

>> b) The present barline-interface is "pure" WYSIWYG
> 
> And one of the points of LilyPond is that it does the right things
> visually without requiring the user for everything.

I always understood it as WYSIWYG and I think it a good change to really
have that. Semantical interpretations should come with words if that is
wanted.
\finalBar is clearer than \bar "|.", because "|." is no common symbol
for end of staff (I would say).

> 
>> c)
>> The first for any user noticable novelty is the change from \bar ":|"
>> to \bar ":|."
>> dito for other repeat-signs.
>> This is covered by a convert-rule.
> 
> Sure.  The question is not how to avoid users having to change habits.
> The question is what the best user interface would be for someone not
> having previous exposure to LilyPond.
> 
>> Ok, you'd prefer processing ":|" as colon-thin-thick-barline with no
>> need for a converting-rule.
>> Well, here I think different: I do like the "pure" WYSIWYG-approach
>> and I'm not convinced that a semi-WYSIWYG-approach would really be
>> more intuitive.
> 
> You are assuming that the average user is aware of the visual
> composition of repeat signs.  But that's LilyPond's responsibility.

As I said, I always expected WYSIWYG here and I expected Lilypond caring
about when I use \repeat (as I usally do, for standard use cases).

> We use "|." for the end bar not because of its _visual_ properties,
If that is the case, I would say \bar "." is more logical. But
punctuation symbols are not the most intuitive for logical bar lines, imho.

>> My first thought would be: Let us improve the documentation.
The example, I got, was very instructive. This would be a good starting
point. But with a clear message, that this is not intended for usual
\repeats.

> 
> I am not sure our spacing procedures have been accepted.  From a user
> interface design point of view, they are O(n^2) which scales rather
> badly.
I am currently reading the docs about spacing (I am working through them
for >8h now). Probably there will be questions, once I am through.

> I think we'd fare better with a user interface specifying before/after
> space of any construct, with LilyPond constructing
> 
> x-y-spacing = max (after-x-spacing, before-y-spacing)


> Misunderstanding here: I was not complaining about your explanation, but
> rather about it being needed in the first place. 
I just did not find a doc for the barline interface, just one thread on
this list. Essentially, I concluded all from these two lines:
\defineBarLine "|.|" #'("|.|" "" "|.|")
%end-of-line, begin-of-line, spanbar

Cheers,
Joram